2002A&A...387..295K

We present an observational study of the spatial variation of the electron temperature in the 30 Doradus Nebula. We used the [OIII](λ4959+λ5007)/λ4363 ratio to estimate the electron temperature at 135 positions in the nebula across three different directions. We analysed long-slit spectrophotometric data of high signal-to-noise in the range of 4100 to 5030Å obtained with the Cassegrain spectrograph attached to the 1.60m telescope of the Laboratorio Nacional de Astrofisica, Brazil. No large-scale electron temperature gradient was detected in 30 Doradus. The electron temperature estimates obtained are fairly homogeneous with a mean value of 10270±140(3σ)K. The compatibility between the present estimates with optical and radio temperature determinations found in the literature for other positions or for the entire nebula corroborates this conclusion. Temperature fluctuations of small amplitude were observed with a variance relative to the mean of t_s²=0.0025 or equivalently with a dispersion of only 5%. The areas with lower surface brightness seem to present slightly higher electron temperatures. This would indicate that the bright arcs of 30 Doradus, which correspond to the densest regions, would have lower electron temperatures than the most diffuse areas.